OPTICAL SENSOR DEVICE
First Claim
1. An optical sensor device comprising:
- a light emitter configured to periodically emit light at a predetermined frequency toward a measurement target;
a light receiver configured to detect at least one of reflected light and diffused light from the measurement target, and to output an electrical signal based on the detected light;
a filter circuit configured to modulate the electrical signal at the predetermined frequency and to output a modulation signal;
an amplifier configured to amplify the modulation signal;
an AD converter configured to convert the modulation signal to a digital signal; and
an arithmetic processing unit coupled to the AD converter and configured to calculate a DC component and an AC component of the electrical signal based on the digital signal.
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Accused Products
Abstract
An optical sensor device includes a light emitter for emitting, to a living body, lights having two wavelengths and blinking at a predetermined frequency, and a light receiver for receiving the lights from the living body. The light receiver outputs first and second detection signals corresponding to the respective wavelengths. A filter circuit extracts, from the first and second detection signals, modulation signals that are obtained with amplitude modulation of signals of the predetermined frequency. The modulation signals are amplified by a post-amplifier and are taken into an arithmetic processing unit after being converted to digital signals by an AD converter. The arithmetic processing unit calculates DC components and AC components of the first and second detection signals by employing the modulation signals converted the digital signals.
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Citations
20 Claims
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1. An optical sensor device comprising:
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a light emitter configured to periodically emit light at a predetermined frequency toward a measurement target; a light receiver configured to detect at least one of reflected light and diffused light from the measurement target, and to output an electrical signal based on the detected light; a filter circuit configured to modulate the electrical signal at the predetermined frequency and to output a modulation signal; an amplifier configured to amplify the modulation signal; an AD converter configured to convert the modulation signal to a digital signal; and an arithmetic processing unit coupled to the AD converter and configured to calculate a DC component and an AC component of the electrical signal based on the digital signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An optical sensor device comprising:
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a light emitter configured to emit light toward a measurement target; a light receiver configured to detect at least one of reflected light and diffused light from the measurement target, and output an electrical signal based on the detected light; a separation circuit configured to separate the electrical signal into a DC component and an AC component; an amplification circuit configured to amplify the DC component and the AC component, at first and second amplification factors, respectively; an AD converter configured to convert the DC component and the AC component to first and second digital signals, respectively; and an arithmetic processing unit configured to restore the DC component and the AC component of the electrical signal by converting the DC component and the AC component output as the first and second digital signals such that an amplitude ratio between the DC component and the AC component output as the digital signals obtains a state before the amplification by the amplification circuit.
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13. An optical sensing method comprising:
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emitting light, by a light emitter, at a predetermined frequency towards a measurement target; detecting, by a light receiver, at least one of reflected light and diffused light from the measurement target; outputting, by the light receiver, an electrical signal based on the detected light; modulating, by a filter circuit, the electrical signal at the predetermined frequency; outputting, by the filter circuit, a modulation signal corresponding to the electrical signal; amplifying, by an amplifier, the modulation signal; converting, by an AD converter, the amplified modulation signal to a digital signal; and calculating, by a processor, a DC component and an AC component of the electrical signal based on the digital signal. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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Specification